MCP79400/MCP79401/MCP79402 2 Battery-Backed I C Real-Time Clock/Calendar with SRAM and Protected EEPROM Device Selection Table Operating Ranges 2 Part Number Protected EEPROM 2-Wire Serial Interface, I C Compatible: 2 -I C clock rate up to 400 kHz MCP79400 Unprogrammed Temperature Range: MCP79401 EUI-48 - Industrial (I): -40C to +85C MCP79402 EUI-64 Packages Timekeeping Features 8-Lead SOIC, MSOP, TSSOP and 2x3 TDFN Real-Time Clock/Calendar (RTCC): - Hours, Minutes, Seconds, Day of Week, Day, General Description Month, Year The MCP7940X Real-Time Clock/Calendar (RTCC) - Leap year compensated to 2399 tracks time using internal counters for hours, minutes, - 12/24-hour modes seconds, days, months, years, and day of week. Oscillator for 32.768 kHz Crystals: Alarms can be configured on all counters up to and including months. For usage and configuration, the - Optimized for 6-9 pF crystals 2 MCP7940X supports I C communications up to On-Chip Digital Trimming/Calibration: 400 kHz. - 1 ppm resolution The open-drain, multi-functional output can be - 129 ppm configured to assert on an alarm match, to output a Dual Programmable Alarms selectable frequency square wave or as a general purpose output. Versatile Output Pin: The MCP7940X is designed to operate using a - Clock output with selectable frequency 32.768kHz tuning fork crystal with external crystal - Alarm output load capacitors. On-chip digital trimming can be used - General purpose output to adjust for frequency variance caused by crystal Power-Fail Timestamp: tolerance and temperature. - Time logged on switchover to and from SRAM and timekeeping circuitry are powered from the Battery mode back-up supply when main power is lost, allowing the device to maintain accurate time and the SRAM Low-Power Features contents. The times when the device switches over to the back-up supply and when primary power returns Wide Voltage Range: are both logged by the power-fail timestamp. - Operating voltage range of 1.8V to 5.5V The MCP7940X features 64 bits of EEPROM which is - Backup voltage range of 1.3V to 5.5V only writable after an unlock sequence, making it ideal Low Typical Timekeeping Current: for storing a unique ID or other critical information. The MCP79401 and MCP79402 are preprogrammed with - Operating from VCC: 1.2 A at 3.3V EUI-48 and EUI-64 addresses, respectively. Custom - Operating from battery backup: 925nA at programming is also available. 3.0V Package Types Automatic Switchover to Battery Backup User Memory SOIC, TSSOP, MSOP TDFN 64-Byte Battery-Backed SRAM X1 1 8 VCC X1 1 8 VCC 64-Bit Protected EEPROM Area: X2 2 7 MFP X2 2 7 MFP - Robust write unlock sequence VBAT3S6CL VBAT 3 6 SCL -EUI-48 MAC address (MCP79401) VSS 4 5 SDA VSS 4 5 SDA -EUI-64 MAC address (MCP79402) - Custom programming available 2011-2018 Microchip Technology Inc. DS20005009G-page 1MCP79400/MCP79401/MCP79402 FIGURE 1-1: TYPICAL APPLICATION SCHEMATIC VCC VCC VCC 8 VCC C 1 X1 X1 6 SCL MCP7940X PIC MCU C 5 2 X2 SDA X2 7 3 MFP VBAT VBAT VSS 4 FIGURE 1-2: BLOCK DIAGRAM VCC Power Control Power-Fail VSS and Switchover Timestamp VBAT SCL Control Logic Configuration 2 I C Interface and Addressing SDA Seconds SRAM EEPROM Minutes X1 32.768 kHz Hours Clock Divider Oscillator X2 Day of Week Digital Trimming Date Square Wave Month Alarms Output Year MFP Output Logic 2011-2018 Microchip Technology Inc. DS20005009G-page 2 32.768 KHZ